My DS7 skipped first, so a little different from your kiddo. How does she feel about skipping? I agree with what earlier posters have said, that even though a skip may not be enough, it is a better place. It is much easier for teachers to differentiate with kids who are closer to the level they are used to teaching. And the bonus in your situation is that the school has offered a grade skip or subject acceleration. Since the school sees the value in both types of acceleration, in your DD's situation you might be able to swing both (a grade skip plus subject acceleration in the areas she needs it).
Our experience with the skip was that it was not enough in itself, and the school was trying very hard to meet DS's needs with pullouts and differentiation, but pace was really the issue. We ended up transferring to a school for HG kids mid-year, where the classes were a year advanced plus the pace was faster.
The only con we've encountered, which probably won't be an issue with an older kid, is that DS's handwriting was pretty bad compared to the kids in the classes he skipped into. Also, he hadn't had any experience writing much at all, since he skipped first. Also, he complained that gym was too hard sometimes. (He's small for his age on top of being younger than his classmates.)
Some possible cons to think about with acceleration. Your DC may be at a disadvantage in sports or in academic competitions because of the age difference. Our son isn't that much younger (he's a January birthday, so 5 months past the cutoff), and not too athletic, so we haven't had to deal with competitive stuff yet, esp. since he's just a rising 3rd grader. Maybe others can speak to that if you have questions.
